[Dnsmasq-discuss] Strange DNS failure, what might be wrong?

[Chris Green]

I'm running  dnsmasq version 2.91 on two Debian 13 systems and version
2.93 on my Asus rt-be92u router running Asuswrt-merlin.

It has all been working quite happily for quite a long time but I have
just come across an oddity. It fails with a timeout when I look up the
address of idnet.com, but looking up idnet.co.uk works OK.  So, I see on
one of the Debian systmes running dnsmasq just as a caching DNS server:-

    chris$ host idnet.com
    ;; communications error to 127.0.0.1#53: timed out
    ;; communications error to 127.0.0.1#53: timed out
    ;; no servers could be reached
    chris$ host idnet.co.uk
    idnet.co.uk has address 212.69.36.50
    idnet.co.uk mail is handled by 10 mx10.idnet.net.
    idnet.co.uk mail is handled by 10 mx20.idnet.net.
    chris$ 

Similarly from another system which doesn't have DNS caching and thus
uses the Asus router directly for DNS:-

    chris at backup$ host idnet.com
    ;; communications error to 192.168.1.1#53: timed out
    ;; communications error to 192.168.1.1#53: timed out
    ;; no servers could be reached
    chris at backup$ host idnet.co.uk
    idnet.co.uk has address 212.69.36.50
    idnet.co.uk mail is handled by 10 mx10.idnet.net.
    idnet.co.uk mail is handled by 10 mx20.idnet.net.
    chris at backup$ 

All other addresses seem to get looked up OK, whether .com or .co.uk or
other TLDs, it's just idnet.com that fails.

The 'special' thing about idnet.com and idnet.co.uk is that iDnet is my
ISP (via CityFibre).

Other systems find idnet.com OK, it's not a real failure:-

    chris at gvps$ host idnet.co.uk
    idnet.co.uk has address 212.69.36.50
    idnet.co.uk mail is handled by 10 mx10.idnet.net.
    idnet.co.uk mail is handled by 10 mx20.idnet.net.
    chris at gvps$ host idnet.com
    idnet.com has address 212.69.36.50
    idnet.com mail is handled by 10 mx1.idnet.net.
    idnet.com mail is handled by 20 mx2.idnet.net.
    chris at gvps$ 

(gvps is a virtual server not on my LAN)


I am using dnsmasq via Network Manager, i.e. there's a line in the
NetworkMaager.conf file:-
    dns=dnsmasq
There's no explicit dnsmasq.conf file.

What puzzles me is how I'm getting a timeout for one specific name. I
can't find any references to 'idnet.com' in the whole of /etc nor
anywhere in the Asus router's configuration.

Can anyone suggest what may be wrong or give me an idea on how to
diagnose it?


-- 
Chris Green